Silo Level Indication - Feedback and Alarm System

A recent breakdown of an existing silo level measurement system lead to a local manufacturing company to run out of product. The existing system was providing false information about the contents of the silos leading to a shortage.

The dated system was now redundant and unsupported by the manufacturer. It also relied upon worn COAX cables between the control panel and the roof of the silos for feedback. However, the control panel was still in good condition as it was located inside a services building. 

We decided to rebuild the control panel back plate a new siemens S7-1200 PLC and install a 4" touch screen HMI to the panel door. New Vega-PULS level probes were installed on the silos with screened cabling carrying the 4-20mA signals routed to the control panel.

Signal isolator/amplifiers were installed that duplicated the 4-20mA signal allowing another system on the site to display, trend and archive the valuable data.

The HMI was programmed to display the levels of the silos as a percentage and also allow for the operator to set a high and low level alarms.

These alarms trigger the new 24vdc 4 pole relays to allow for interlocking to the silo feed and distribution system ensuring the customer cannot over fill or run out of product.

The new system was designed, built, installed and commissioned with 4 days in order to minimise downtime for the client.